Pump unloading valve



May 26, 1953 w. D. TEAG'UE, JR

PUMP UNLOADING VALVE Filed March 21, 1947 lNVENTOR [L/HL 75/? D. TEWEUE, JR-

W WM ATTORNEY Patented May 26, 1953 PUMP UNLOADING VALVE Walter Dorwin Teaguc, Jr., Alpine, N. J assignor to Bendix Aviation Corporation, Teterboro, N. J a corporation of Delaware I Application March 21, 1947, Serial No. 736,318

3 Claims.

' and closing, of an unloading valve, is to provide means including a plurality of pistons operative as one piston in effecting the opening and closing movements.

Another object is to provide novel means to compensate for discrepancies which may occur in the alignment of such elements.

Another object is to provide novel means for draining a spring or pressure chamber to the closed side of a valve while the valve is in normal position closing the drain to a main fluid.

Another object is to provide a valve of the type noted which is light in weight.

Another object is to provide an unloading valve that is simple and durable in construction, economical to manufacture and effective in its operation.

These and other objects and features of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawing. It is to be understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawing:

Figure 1 is a side view in section of a valve constructed in accordance with the invention in one form;

Figure 2 is an elevation taken at right angles to Figure 1; and Figure 3 is an enlarged detail of a modification of a valve and piston element, as viewed in Figure l.

Referring to the drawing, the device comprises a housing including portions I2, I4 and [5, a through bore conduit IS in the portion I2 including an inlet l8 adapted to receive fluid from a pump, a check valve chamber 20, an outlet 22 adapted to receive a tube coupling 24 for com munication with a'fiuid pressure accumulator, a spring chamber 26 in the housing portion 14, and a cylinder 28 in the housing portion l5 and located between the inlet l8 and the check valve chamber 20 and extending at a right'angle or transversely to the conduit l-B between the spring chamber 26 and one side 30 of the conduit. A valve seat 32 at the opposite side of the conduit opens into one end 34 of a drain chamber 36, and, for facility of manufacture, may have a diameter substantially the same as the outer diameter of the cylinder 28. A second cylinder 38 of smaller inner diameter than, and aligned with, the first cylinder 28, extends from the other end 40 of the drain chamber 36. A drain 42 communicates with the drain chamber, and a passage 44 communicates between the second cylinder 38 and the outlet side of the check valve chamber 20 downstream of the inlet l8 and the pump when connected thereto.

- A check valve 48, in the chamber 20, is normally biased by a spring against a seat 52 in the conduit l6, and opens under pump pressure to the outlet 22, the check valve being provided with side passages 54 for this purpose.

A retainer 49, for the spring 50 andin this instance seated on the coupling 24, comprises upper and lower portions joined, as by three legs 5| to provide free fluid flow past or through the retainer.

A pressure relief piston56 includes a body 58 in the first cylinder 28 and a seating portion or valve disc 60 for the seat 32 normally closing the drain chamber 36 relative to the conduit l6, and in this instance is provided with an extension 62 in the drain chamber 36. An axial duct 64 normally communicates between the spring chamber 26 and the drain chamber 36 through an orifice 66 in the extension62. Also, in this instance, a plane face 63, at the right hand or valve closing side of the portion 60, it at right angles to the valve axis.

A compression spring 68 acts between a seat 69 on the relief piston 56 and a seat 10 on a screw 12, and normally biases the relief piston to close the drain chamber 36. The seat 10, the screw 12, and a lock nut device 14 constitute means whereby the pressure of the spring 68 may be ad- 'Justed from a position exteriorly of the spring chamber 26.

In the form of Figure 1, a separate piston 16, in the second cylinder 38, is responsive to fluid pressure in the passage 44 to engage and bias the relief piston 56 again'st the action of the spring 68, and. against fluid pressure in the con- 3 duit [6. The pistons 56 and 16 may be one integral member 80, as shown in Figure 3, but having them separate as shown, compensates for discrepancies in alignment which may occur between the cylinders 28 and 38.

The relief piston 56 includes a constricted portion 18 between the piston body 58 and the seating portion *6l3 nermally across th'e conduit is providing for fluid passage through the conduit past the piston.

In this instance, the cross sectional area of the seating portion 60, minus the cross sectional area of the relief piston body 58, is equar'to substantially three tenths of the-cross sectional af'ea of the separate or second piston 16.

In operation, when the pressure in the accumulator, represented by the pressure in the check valve chamber 20 and the passage 34, attains a predetermined value, the second piston '15, acting against the spring 63, pushes the relief piston 56 to the left, thus unseating the portion 60 from the seat 3-2 and providing communication from the inlet t8 to the drain chamber 36 and the drain '42, to unload, and reduce the average power used in operating the pump. Upon the first unseating movement of the portion '60, the fluid pressure in the conduit I5, which had been assisting 'the spring '68 to hold the portion 60 closed, is immediately nullified, so .that the valve opens quiokly-andcompletely. It-closes in the same manner.

To have the valve open, as describedpat a pressure, for example, such as '1500 pounds per square inch, and close at say 1000 p. s. i., the diameter of the seating portion or valve disc 60 is made slightly larger than that o f the piston 56. Also, with the valve of approximately the size "originally illustrated herein, the cross sectional areas are substantially above set forth, so that the spring and hydraulic pr'essu'res acting on the piston 56, the valve disc St and the piston 16 are considerably in "excess of possible frictional forces.

The 'duc't fi land the orifice 'fiii operate to drain the chamber 26 of f lu'id which may pass thereto past the piston 56-, so that the "device "may be easily efiectively sealed and the piston 56 maintain'ed'free from effects of accumulated fluid in the chamber.

As shown in Figure 3, the pistons 58 and 1 6 are in one --inte'gr'al piecegand the race 68, instead of being plane and at right Y angles to the valve axis, in the above-described form, is of dish'e'd or frusto conica l shape symmetric-a1 to the axis to further ensure "good sealing entirelyaround the 'p'erim'ete'rof the portion fill. e

"In this figure, the piston 16 has a cross sec"- tional area Al, "the portion 60 has an area A3, and thepisto'n 58 has an area To determine the pressure-spread between loading'an'd unloading par-ts:

A1=the area of the piston it. I A2=the area-A of the seating portion fifl minus the area Ai'of thebody 58.

F=the force of the spring 68. A Po=iinloading pressure at which the valveopens. P=loading pressure "at which the valve closes.

At the point of opening:

POA1 POA2+F At the point of closing:

A1 P 0/ P 0- A1 A2 Thus, the relation of A1 to (AIAV2) governs the pressure "sbread between o emng and clos- The spring force F governs the absolute values or the opening and closing pressures.

'Although only two embodiments of the invention have been illustrated and described, various changes in the form and relative arrangements of the parts, which will now appear to those skilled "in the art, may be made without departing from the scopeof the invention. Reference is, therefore, to be had to the appended claims for a definitionof the limits of the invention.

What is claimed is:

- 1-. A'valve assembly comprising a' housing :having a through conduit including, in alignment, an inlet adapted to receive fluid under pressure from an outside source, a check valve chamber, and an outlet adapted to communicate with a fluid pressure accumulator, a valve seat in said chamber at the inlet side thereof, a piston :slidably mounted in said chamber and adapted at one end thereof to'engage said'valve seat, aspring normally operative to 'holdsaid-piston in engagement with said valve seat, saidpiston having a side passage providing for the passage of fluid through said check valve chamberwhensaid pis- Therefore ton "is moved away from said valve seat in response to inlet fluid pressure, 'saidpis'ton being responsive to iiu'id'pressure at said outlet to close said check valve chamber to inlet fluid pressure, said housing having a drain chamber communieating with said through conduit including a valve seat normally disposedto said conduit, a drain communicating with said drain chamber, a relief piston having "a body portion 'slidably mounted in said housing and a valve portion of reater cross-sectional area than said body por tion, said valveportion being adapted to engage the valve seat'of said drain chamber, spring means adjustablymounted insaid housing and operatively associated with said relief piston to effectarpredetermined bias on said relief piston in a direction whereby said Valve portion engages the valve seat of said drain'chamber, said relief pistonhaving a constricted .portion intermediate the body andvalve portion thereof and disposed normally across-said through conduit, said constricted portion defining relatively different pressureareas on-said bodyand valve portions of said relief piston, the effective pressure area of .said valve ,portion being greater than the eifective pressure area of said body portionand disposed in said conduit whereby fluid pressure passing through 'said-conduit -and'around said constricted portioneffe'cts :a predetermined bias on said arelief :piston in a direction augmenting theibiasing efieot of said spring means when said 'valveportion is engaged with said valve seat a-secondapiston of lesser-cross-sectionaLareathan the body and valve portions ofsaid relief piston slidably mounted in said housing and having .one end thereof .operativelyassociated With the valve portionof said-relief piston, a ,passage communicating with thecheck valve chamber :at the outlet side thereof andwi-th the opposed-end of saidssecond .piston whereby .1 fluid pressure .at the I outlet side of-said check valvechamberin excess of the predetermined biasing of the relief piston as aforesaid, actuate said second piston to overcome the predetermined biasing of said relief piston, thereby unseating the valve portion of the relief piston from said valve seat and permitting fluid from said inlet to flow through said drain chamber to said drain, and simultaneously moves the piston in said check valve chamber in a direction to close said check valve chamber to said inlet, said relatively different pressure areas being effective When said valve portion is unseated from said valve seat to assist movement of said relief piston against said spring means.

2. A valve assembly comprising a housing having a through conduit including, in alignment, an inlet adapted to receive fluid under pressure from an outside source, a check valve chamber, and an outlet adapted to be connected to a fluid pressure accumulator, a check valve in said check valve chamber opening to said outlet and responsive to the fluid pressure at both said inlet and outlet, said check valve including a piston hav ing a side passage providing for fluid flow through said check valve chamber when said check valve is opened in response to inlet fluid pressure, a drain chamber in said housing normally disposed to said conduit and having a valve seat adjacent said conduit, a drain in communication with said drain chamber, a relief piston having a body portion mounted for reciprocating movement in said housing and having a constricted portion extending across said conduit, a valve head formed at one end of said constricted portion adapted to engage said valve seat to close communication between said conduit and drain chamber, said valve head having a greater cross-sectional area than said body portion, said constricted portion defining relatively different pressure areas on the body and valve head portions, the effective pressure area on said valve portion being greater than the effective pressure area of said body portion and disposed in said conduit for effecting a predetermined biasing load on said relief piston when fluid under pressure passes through said conduit and around said constricted portion, spring means adjustably mounted in said housing and operatively associated with said relief piston for efiecting a predetermined load on said relief piston augmenting the biasing load produced by the different pressure areas on the body and valve head of said relief piston, the predetermined loading of the relief piston normally being operative to hold said valve head in engagement with said valve seat, relief piston operating means mounted for reciprocation in said housing and operatively associated with the valve head of said relief piston for effecting the unseating of said valve head, and a passage in said housing between the outlet side of said check valve chamber and a portion of said relief piston operating means whereby said relief piston operating means is actuated in response to a predetermined fluid pressure at said outlet to move the relief piston against the predetermined biasing loads aforesaid, thereby permitting fluid flow from said inlet through said drain chamber to said drain, said relatively diiierent pressure areas being effective in response to said last mentioned flow to assist movement of said relief piston against said spring means.

3. In combination a valve comprising a through conduit including an inlet and outlet in alignment therewith, a check valve in said through conduit opening to the outlet, said check valve including a check-valve piston movable in response to both inlet and outlet pressure, a drain communicating with said through conduit, a main piston at right angle to said through conduit and movable to a position to close said drain from said through conduit, spring means operatively associated with one end of said main piston for moving and maintaining said main piston to and in said closed position, said main piston having a constricted portion extending across said through conduit, said constricted portion defining relatively diiferent pressure areas on said main piston, the effective pressure area of the main piston closing said drain being greater than the effective pressure area of the main piston remote therefrom, said pressure areas being positioned in said conduit and operative in response to pressure flow in said conduit from said inlet through said outlet to augment said spring means in maintaining said main piston in said closed position, a smaller piston at the opposite end of said main piston, and a passage from said outlet adapted tosubject said smaller piston to back pressure therefrom to overcome said spring and pressure areas maintaining said main .piston in closed position, and thereby establish communication between said through conduit and said drain, said pressure areas of said main piston being efiective to assist said smaller piston to overcome said spring means upon the opening of said conduit to said drain.

WALTER DORWIN TEAGUE JR.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,636,561 Hazard July 19, 1927 2,015,801 Johnson Oct. 1, 1935 2,210,295 Johnson Aug. 10, 1940 2,271,031 Parker Jan. 27,1942 2,372,016 Rockwell Mar. 20, 1945 2,421,133 Towler May 27, 1947 2,429,489 Roth Oct. 21, 1947 2,437,480 Pugh Mar. 9, 1948 2,513,304 Fraser July 4, 1950 

